RESUMO
Most indigenous ethnias from Northern Argentina live in rural areas of "the Gran Chaco" region, where Trypanosoma cruzi is endemic. Serological and parasitological features have been poorly characterized in Aboriginal populations and scarce information exist regarding relevant T. cruzi discrete typing units (DTU) and parasitic loads. This study was focused to characterize T. cruzi infection in Qom, Mocoit, Pit'laxá and Wichi ethnias (N=604) and Creole communities (N=257) inhabiting rural villages from two highly endemic provinces of the Argentinean Gran Chaco. DNA extracted using Hexadecyltrimethyl Ammonium Bromide reagent from peripheral blood samples was used for conventional PCR targeted to parasite kinetoplastid DNA (kDNA) and identification of DTUs using nuclear genomic markers. In kDNA-PCR positive samples from three rural Aboriginal communities of "Monte Impenetrable Chaqueño", minicircle signatures were characterized by Low stringency single primer-PCR and parasitic loads calculated using Real-Time PCR. Seroprevalence was higher in Aboriginal (47.98%) than in Creole (27.23%) rural communities (Chi square, p=4.e(-8)). A low seroprevalence (4.3%) was detected in a Qom settlement at the suburbs of Resistencia city (Fisher Exact test, p=2.e(-21)).The kDNA-PCR positivity was 42.15% in Aboriginal communities and 65.71% in Creole populations (Chi square, p=5.e(-4)). Among Aboriginal communities kDNA-PCR positivity was heterogeneous (Chi square, p=1.e(-4)). Highest kDNA-PCR positivity (79%) was detected in the Qom community of Colonia Aborigen and the lowest PCR positivity in two different surveys at the Wichi community of Misión Nueva Pompeya (33.3% in 2010 and 20.8% in 2014). TcV (or TcII/V/VI) was predominant in both Aboriginal and Creole communities, in agreement with DTU distribution reported for the region. Besides, two subjects were infected with TcVI, one with TcI and four presented mixed infections of TcV plus TcII/VI. Most minicircle signatures clustered according to their original localities, but in a few cases, signatures from one locality clustered with signatures from other village, suggesting circulation of the same strains in the area. Parasitic loads ranged from undetectable to around 50 parasite equivalents/mL, showing higher values than those generally observed in chronic Chagas disease patients living in urban centers of Argentina. Our findings reveal the persistence of high levels of infection in these neglected populations.
Assuntos
Doença de Chagas/epidemiologia , DNA de Cinetoplasto/genética , Doenças Endêmicas , Filogenia , Trypanosoma cruzi/genética , Adolescente , Adulto , Idoso , Argentina/epidemiologia , Doença de Chagas/etnologia , Doença de Chagas/parasitologia , Criança , Pré-Escolar , Humanos , Indígenas Sul-Americanos , Lactente , Pessoa de Meia-Idade , Carga Parasitária , População Rural , Estudos Soroepidemiológicos , Trypanosoma cruzi/classificação , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/patogenicidade , Populações VulneráveisRESUMO
The competence of reservoir hosts of vector-borne pathogens is directly linked to its capacity to infect the vector. Domestic dogs and cats are major domestic reservoir hosts of Trypanosoma cruzi, and exhibit a much higher infectiousness to triatomines than seropositive humans. We quantified the concentration of T. cruzi DNA in the peripheral blood of naturally-infected dogs and cats (a surrogate of intensity of parasitemia), and evaluated its association with infectiousness to the vector in a high-risk area of the Argentinean Chaco. To measure infectiousness, 44 infected dogs and 15 infected cats were each exposed to xenodiagnosis with 10-20 uninfected, laboratory-reared Triatoma infestans that blood-fed to repletion and were later individually examined for infection by optical microscopy. Parasite DNA concentration (expressed as equivalent amounts of parasite DNA per mL, Pe/mL) was estimated by real-time PCR amplification of the nuclear satellite DNA. Infectiousness increased steeply with parasite DNA concentration both in dogs and cats. Neither the median parasite load nor the mean infectiousness differed significantly between dogs (8.1Pe/mL and 48%) and cats (9.7Pe/mL and 44%), respectively. The infectiousness of dogs was positively and significantly associated with parasite load and an index of the host's body condition, but not with dog's age, parasite discrete typing unit and exposure to infected bugs in a random-effects multiple logistic regression model. Real-time PCR was more sensitive and less time-consuming than xenodiagnosis, and in conjunction with the body condition index, may be used to identify highly infectious hosts and implement novel control strategies.
Assuntos
Doenças do Gato/diagnóstico , Doença de Chagas/veterinária , Reservatórios de Doenças , Doenças do Cão/diagnóstico , Triatoma/parasitologia , Trypanosoma cruzi/isolamento & purificação , Animais , Doenças do Gato/parasitologia , Gatos , Doença de Chagas/parasitologia , DNA Satélite/genética , Doenças do Cão/parasitologia , Cães , Feminino , Humanos , Insetos Vetores/parasitologia , Parasitemia/parasitologia , Parasitemia/veterinária , Reação em Cadeia da Polimerase em Tempo Real , Trypanosoma cruzi/genética , Trypanosoma cruzi/patogenicidade , XenodiagnósticoRESUMO
Treatment for Chagas disease with currently available medications is recommended universally only for acute cases (all ages) and for children up to 14 years old. The World Health Organization, however, also recommends specific antiparasite treatment for all chronic-phase Trypanosoma cruzi-infected individuals, even though in current medical practice this remains controversial, and most physicians only prescribe palliative treatment for adult Chagas patients with dilated cardiomyopathy. The present opinion, prepared by members of the NHEPACHA network (Nuevas Herramientas para el Diagnóstico y la Evaluación del Paciente con Enfermedad de Chagas/New Tools for the Diagnosis and Evaluation of Chagas Disease Patients), reviews the paradigm shift based on clinical and immunological evidence and argues in favor of antiparasitic treatment for all chronic patients. We review the tools needed to monitor therapeutic efficacy and the potential criteria for evaluation of treatment efficacy beyond parasitological cure. Etiological treatment should now be mandatory for all adult chronic Chagas disease patients.
Assuntos
Cardiomiopatia Chagásica/tratamento farmacológico , Gerenciamento Clínico , Nifurtimox/uso terapêutico , Nitroimidazóis/uso terapêutico , Tripanossomicidas/uso terapêutico , Adolescente , Adulto , Anticorpos Antiprotozoários/sangue , Cardiomiopatia Chagásica/imunologia , Cardiomiopatia Chagásica/parasitologia , Cardiomiopatia Chagásica/patologia , Criança , Doença Crônica , Esquema de Medicação , Humanos , Guias de Prática Clínica como Assunto , Ensaios Clínicos Controlados Aleatórios como Assunto , Índice de Gravidade de Doença , Resultado do Tratamento , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/patogenicidade , Trypanosoma cruzi/fisiologiaRESUMO
Organ transplantation (TX) is a novel transmission modality of Chagas disease. The results of molecular diagnosis and characterization of Trypanosoma cruzi acute infection in naïve TX recipients transplanted with organs from infected deceased donors are reported. Peripheral blood and cerebrospinal fluid samples from the TX recipients of organs from infected donors were prospectively and sequentially studied for detection of T. cruzi by means of kinetoplastid DNA polymerase chain reaction (kDNA-PCR). In positive blood samples, a PCR algorithm for identification of T. cruzi Discrete Typing Units (DTUs) and quantitative real-time PCR (qPCR) to quantify parasitic loads were performed. Minicircle signatures of T. cruzi infecting populations were also analyzed using restriction fragment length polymorphism (RFLP)-PCR. Eight seronegative TX recipients from four infected donors were studied. In five, the infection was detected at 68.4 days post-TX (36-98 days). In one case, it was transmitted to two of three TX recipients. The comparison of the minicircle signatures revealed nearly identical RFLP-PCR profiles, confirming a common source of infection. The five cases were infected by DTU TcV. This report reveals the relevance of systematic monitoring of TX recipients using PCR strategies in order to provide an early diagnosis allowing timely anti-trypanosomal treatment.
Assuntos
Doença de Chagas/diagnóstico , Transplante de Órgãos/efeitos adversos , Adolescente , Adulto , Idoso , Algoritmos , DNA de Cinetoplasto/genética , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Fatores de Tempo , Doadores de Tecidos , Trypanosoma cruzi/genética , Adulto JovemRESUMO
Domestic dogs and cats are major domestic reservoir hosts of Trypanosoma cruzi and a risk factor for parasite transmission. In this study we assessed the relative performance of a polymerase chain reaction assay targeted to minicircle DNA (kDNA-PCR) in reference to conventional serological tests, a rapid dipstick test and xenodiagnosis to detect T. cruzi infection in dogs and cats from an endemic rural area in northeastern Argentina. A total of 43 dogs and 13 cats seropositive for T. cruzi by an immunosorbent assay (ELISA) and an indirect hemagglutination assay (IHA), which had been examined by xenodiagnosis, were also tested by kDNA-PCR. kDNA-PCR was nearly as sensitive as xenodiagnosis for detecting T. cruzi-infectious dogs and cats. kDNA-PCR was slightly more sensitive than xenodiagnosis in seropositive dogs (91% versus 86%, respectively) and cats (77% against 54%, respectively), but failed to detect all of the seropositive individuals. ELISA and IHA detected all xenodiagnosis-positive dogs and both outcomes largely agreed (kappa coefficient, κ=0.92), whereas both assays failed to detect all of the xenodiagnosis-positive cats and their agreement was moderate (κ=0.68). In dogs, the sensitivity of the dipstick test was 95% and agreed closely with the outcome of conventional serological tests (κ=0.82). The high sensitivity of kDNA-PCR to detect T. cruzi infections in naturally infected dogs and cats supports its application as a diagnostic tool complementary to serology and may replace the use of xenodiagnosis or hemoculture.
Assuntos
Doenças do Gato/diagnóstico , Doença de Chagas/veterinária , Testes Diagnósticos de Rotina/métodos , Doenças do Cão/diagnóstico , Parasitologia/métodos , Trypanosoma cruzi/isolamento & purificação , Medicina Veterinária/métodos , Animais , Argentina , Doenças do Gato/parasitologia , Gatos , Doença de Chagas/diagnóstico , Doença de Chagas/parasitologia , Doenças do Cão/parasitologia , Cães , Técnicas de Diagnóstico Molecular/métodos , Sensibilidade e Especificidade , Testes Sorológicos/métodos , Trypanosoma cruzi/genética , Trypanosoma cruzi/imunologiaRESUMO
The discrete typing units (DTUs) of Trypanosoma cruzi that infect domestic dogs and cats have rarely been studied. With this purpose we conducted a cross-sectional xenodiagnostic survey of dog and cat populations residing in 2 infested rural villages in Pampa del Indio, in the humid Argentine Chaco. Parasites were isolated by culture from 44 dogs and 12 cats with a positive xenodiagnosis. DTUs were identified from parasite culture samples using a strategy based on multiple polymerase-chain reactions. TcVI was identified in 37 of 44 dogs and in 10 of 12 cats, whereas TcV was identified in 5 dogs and in 2 cats -a new finding for cats. No mixed infections were detected. The occurrence of 2 dogs infected with TcIII -classically found in armadillos- suggests a probable link with the local sylvatic transmission cycle involving Dasypus novemcinctus armadillos and a potential risk of human infection with TcIII. Our study reinforces the importance of dogs and cats as domestic reservoir hosts and sources of various DTUs infecting humans, and suggests a link between dogs and the sylvatic transmission cycle of TcIII.
Assuntos
Doenças do Gato/parasitologia , Doença de Chagas/veterinária , Doenças do Cão/parasitologia , População Rural , Trypanosoma cruzi/classificação , Trypanosoma cruzi/genética , Animais , Argentina/epidemiologia , Doenças do Gato/epidemiologia , Doenças do Gato/transmissão , Gatos , Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Doença de Chagas/transmissão , Reservatórios de Doenças/parasitologia , Doenças do Cão/epidemiologia , Doenças do Cão/transmissão , Cães , Humanos , Insetos Vetores/parasitologia , Triatoma/parasitologia , Trypanosoma cruzi/isolamento & purificação , XenodiagnósticoRESUMO
We assessed the distribution of Trypanosoma cruzi Discrete Typing Units (DTUs) in domestic and peridomestic Triatoma infestans and Triatoma sordida specimens collected in a well-defined rural area in Pampa del Indio, northeastern Argentina. Microscopically-positive bugs were randomly selected with a multi-level sampling design, and DTUs were identified using direct PCR strategies. TcVI predominated in 61% of 69 T. infestans and in 56% of 9 T. sordida. TcV was the secondary DTU in T. infestans (16%) and was found in 1 T. sordida specimen (11%). Three T. sordida (33%) were found infected with TcI, a DTU also identified in local Didelphis albiventris opossums. Mixed DTU infections occurred rarely (5%) and were detected both directly from the bugs' rectal ampoule and parasite cultures. The identified DTUs and bug collection sites of T. infestans were significantly associated. Bugs infected with TcV were almost exclusively captured in domiciles whereas those with TcVI were found similarly in domiciles and peridomiciles. All mixed infections occurred in domiciles. TcV-infected bugs fed more often on humans than on dogs, whereas TcVI-infected bugs showed the reverse pattern. T. sordida is a probable sylvatic vector of TcI linked to D. albiventris, and could represent a secondary vector of TcVI and TcV in the domestic/peridomestic cycle.
Assuntos
Triatoma/parasitologia , Trypanosoma cruzi/genética , Animais , Animais Domésticos/parasitologia , Argentina , Cães , Ensaio de Imunoadsorção Enzimática , Genótipo , Humanos , Insetos Vetores/parasitologia , Reação em Cadeia da PolimeraseRESUMO
Little is known about the sylvatic transmission cycle of Trypanosoma cruzi in the Gran Chaco ecoregion. We conducted surveys to identify the main sylvatic hosts of T. cruzi, parasite discrete typing units and vector species involved in Pampa del Indio, a rural area in the humid Argentinean Chaco. A total of 44 mammals from 14 species were captured and examined for infection by xenodiagnosis and polymerase chain reaction amplification of the hyper-variable region of kinetoplast DNA minicircles of T. cruzi (kDNA-PCR). Ten (22.7%) mammals were positive by xenodiagnosis or kDNA-PCR. Four of 11 (36%) Didelphis albiventris (white-eared opossums) and six of nine (67%) Dasypus novemcinctus (nine-banded armadillos) were positive by xenodiagnosis and or kDNA-PCR. Rodents, other armadillo species, felids, crab-eating raccoons, hares and rabbits were not infected. Positive animals were highly infectious to the bugs that fed upon them as determined by xenodiagnosis. All positive opossums were infected with T. cruzi I and all positive nine-banded armadillos with T. cruzi III. Extensive searches in sylvatic habitats using 718 Noireau trap-nights only yielded Triatoma sordida whereas no bug was collected in 26 light-trap nights. Four armadillos or opossums fitted with a spool-and-line device were successfully tracked to their refuges; only one Panstrongylus geniculatus was found in an armadillo burrow. No sylvatic triatomine was infected with T. cruzi by microscopical examination or kDNA-PCR. Our results indicate that two independent sylvatic transmission cycles of T. cruzi occur in the humid Chaco. The putative vectors of both cycles need to be identified conclusively.
Assuntos
Doença de Chagas/parasitologia , Doença de Chagas/veterinária , Reservatórios de Doenças , Vetores de Doenças , Trypanosoma cruzi/isolamento & purificação , Trypanosoma cruzi/patogenicidade , Animais , Animais Selvagens , Argentina , Doença de Chagas/transmissão , DNA de Cinetoplasto/química , DNA de Cinetoplasto/genética , DNA de Protozoário/química , DNA de Protozoário/genética , Humanos , Umidade , Estágios do Ciclo de Vida , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , População Rural , Análise de Sequência de DNARESUMO
Infection with Bartonella spp may cause cardiac arrhythmias, myocarditis and endocarditis in humans. The aim of the present study was to evaluate a possible association between Bartonella spp bacteremia and endocarditis, arrhythmia and Chagas cardiomyopathy in patients from Brazil and Argentina. We screened for the presence of bacterial 16S rRNA in human blood by PCR using oligonucleotides to amplify a 185-bp bacterial DNA fragment. Blood samples were taken from four groups of subjects in Brazil and Argentina: i) control patients without clinical disease, ii) patients with negative blood-culture endocarditis, iii) patients with arrhythmias, and iv) patients with chronic Chagas cardiomyopathy. PCR products were analyzed on 1.5% agarose gel to visualize the 185-bp fragment and then sequenced to confirm the identity of DNA. Sixty of 148 patients (40.5%) with cardiac disease and 1 of 56 subjects (1.8%) from the control group presented positive PCR amplification for Bartonella spp, suggesting a positive association of the bacteria with these diseases. Separate analysis of the four groups showed that the risk of a Brazilian patient with endocarditis being infected with Bartonella was 22 times higher than in the controls. In arrhythmic patients, the prevalence of infection was 45 times higher when compared to the same controls and 40 times higher for patients with Chagas cardiomyopathy. To the best of our knowledge this is the first report of the association between Bartonella spp bacteremia and Chagas disease. The present data may be useful for epidemiological and prevention studies in Brazil and Argentina.
Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Arritmias Cardíacas/microbiologia , Bacteriemia/microbiologia , Infecções por Bartonella/complicações , Cardiomiopatia Chagásica/complicações , Endocardite Bacteriana/microbiologia , Argentina , Brasil , Estudos de Casos e Controles , DNA Bacteriano/análiseRESUMO
Infection with Bartonella spp may cause cardiac arrhythmias, myocarditis and endocarditis in humans. The aim of the present study was to evaluate a possible association between Bartonella spp bacteremia and endocarditis, arrhythmia and Chagas cardiomyopathy in patients from Brazil and Argentina. We screened for the presence of bacterial 16S rRNA in human blood by PCR using oligonucleotides to amplify a 185-bp bacterial DNA fragment. Blood samples were taken from four groups of subjects in Brazil and Argentina: i) control patients without clinical disease, ii) patients with negative blood-culture endocarditis, iii) patients with arrhythmias, and iv) patients with chronic Chagas cardiomyopathy. PCR products were analyzed on 1.5% agarose gel to visualize the 185-bp fragment and then sequenced to confirm the identity of DNA. Sixty of 148 patients (40.5%) with cardiac disease and 1 of 56 subjects (1.8%) from the control group presented positive PCR amplification for Bartonella spp, suggesting a positive association of the bacteria with these diseases. Separate analysis of the four groups showed that the risk of a Brazilian patient with endocarditis being infected with Bartonella was 22 times higher than in the controls. In arrhythmic patients, the prevalence of infection was 45 times higher when compared to the same controls and 40 times higher for patients with Chagas cardiomyopathy. To the best of our knowledge this is the first report of the association between Bartonella spp bacteremia and Chagas disease. The present data may be useful for epidemiological and prevention studies in Brazil and Argentina.